Cam member for actuating and/or restraining the motion of a bail

Abstract

A simplified linkage and cam member having first and second cam surfaces for interacting with a bail to drive said bail between first and second limits is provided. The cam surfaces restrict the movement of the bail when the bail is at either limit. However, when the bail is intermediate of the limits, the relationship of the effective portions of the cam surfaces allow increased bail movement for a given position of the cam member and associated cam surfaces. The structure is particularly well adapted for actuating a bail from a first to a second position wherein forces other than those applied by the cam also act on the bail; and at a critical bail position, the other forces take control and urge continued motion of the bail independent of the cam member. In such structure, the bail is first urged to move by the first cam surface, and at a critical point in its movement, it jumps from the first cam surface to the second cam surface and, for at least part of the remaining motion of the bail, the second cam surface serves to restrain the bail motion. The cam surfaces may be symmetrical in design and provide effective forces on the bail at both the start and end of the motion. The bail may, for example, constitute the actuating arm of a circuit breaker which is within an enclosure and actuated by an external arm coupled by the linkage and cam member.

What is claimed is: 
     
       1. A bail actuating member for initiating movement of a bail along a first predetermined arcuate path in a first plane and between first and second limits and comprising in combination: (a) a cam member supported for arcuate motion in said first plane and having first and second cam surfaces with each cam surface having a first portion which is proximate to the bail when the bail is at either of its first and second limits whereby neither said cam member nor the bail can move when the bail is situated at its first or second limit without simultaneous motion of the other;   (b) said first and second cam surfaces each having second portions which serve to urge and restrict the motion of the bail after it is moved from said first limit and towards said second limit, or after the bail is moved from said second limit and towards said first limit, respectively, in response to motion of said cam member; and wherein   (c) said second portions of said cam surfaces are not both proximate to the bail when the bail is intermediate of said first and second limits whereby the bail is free to move through at least a portion of its travel between said first and second limits without synchronous motion of said cam member.   
     
     
       2. The combination as set forth in claim 1, wherein the bail constitutes the actuating arm of an electrical device within an enclosure and said cam member is coupled to actuating means external of said enclosure. 
     
     
       3. The combination as set forth in claim 1, wherein said first portion of said first cam surface initiates movement of the bail and said second portion of said second cam surface restrains movement of the bail during at least part of the motion of the bail from said first to said second limits. 
     
     
       4. The combination as set forth in claim 1, wherein said cam member and the bail pivot about first and second centers, respectively, during their respective motion. 
     
     
       5. The combination as set forth in claim 4, wherein said first and second centers are on opposite sides of the bail. 
     
     
       6. The combination as set forth in claim 4, wherein said first and second centers are on the same side of the bail.